798 BELL SYSTEM TECHNICAL JOURNAL 



provided data describing present and past weather conditions can be 

 collected from a sufificient number of places. The progress of a weather 

 disturbance can be tracked and the time of its arrival at a given point 

 predicted. By means of a suitable communication system weather 

 reports from observers located along and near an airway can be 

 collected; and it should be possible, therefore, to reduce materially 

 the weather hazard of air transport. 



A full-scale meteorological experiment of this nature is now being 

 conducted in California by the Weather Bureau with the cooperation 

 of the Guggenheim Fund for the Promotion of Aeronautics and of the 

 Pacific Telephone and Telegraph Company. Meteorologists at the 

 Oakland and Los Angeles airports receive several times a day, by 

 long distance telephone, weather data from observers at a large num- 

 ber of selected points in the state. After an exchange of these collected 

 data, these meteorologists forecast flying-weather for aviators starting 

 out over the airway between these airports. The experiment will be 

 continued until the value of the special weather service can be estimated. 



Since the communications problem of safe air transport presented 

 features which in a number of respects were unique, it was referred 

 by the Interdepartmental Committee on Aeronautical Meteorology to 

 experts of the American Telephone and Telegraph Company and Bell 

 Telephone Laboratories. What was desired was the collection of 

 reports from a considerable number of widely distributed observers in 

 a relatively short interval of time, say, from twenty observers in 

 twenty minutes. Naturally, it is not commercially practicable to 

 call the party desired, set up the connections, have him answer and 

 give his data all in the space of one minute. However, an equivalent 

 result has been obtained by evolving a special telephone procedure for 

 the purpose. At the appointed time a team of long-distance telephone 

 operators call up successively the listed observers. Each as he answers 

 is asked to hold the line and wait his turn when the operator connects 

 him to the airport meteorologist. 



It has been found by trial that the weather data can be reported 

 and recorded in thirty seconds. Consequently, the list of observers 

 can be readily gone through if one minute each is allowed. To the 

 Los Angeles and Oakland airports about forty observers are now 

 reporting weather five times a day. These collected reports are 

 exchanged between airports; and airplanes starting over the airway 

 are provided with a forecast of the weather they may expect enroute 

 and upon arrival. 



On the basis of these forecasts, it is hoped that the pilots may be 

 able to avoid bad weather by choosing an alternative route or 



